The invention relates to a harmonic wave quantitative measurement method of a power system. For the current and voltage information of the power system, according to the time sequence and the synchronous equal-time-interval following harmonic wave three-dimensional direction, namely the harmonic wave amplitude and the dynamic variation features of the frequency along with the time, the amplitudes and frequencies of various orders of harmonic waves, the three-dimensional parameter and the three-dimensional curve of the time are obtained through measurement, the amplitude time curve and data of the various orders of three-dimensional following harmonic waves, the frequency time curve and data of the various orders of harmonic waves and the amplitude-versus-frequency curve and data of the various orders of harmonic waves are obtained through measurement, and the harmonic features and data of the power system are obtained through measurement in a quantitative mode. According to the harmonic wave quantitative measurement method of the power system, the harmonic wave impedance and harmonic resonance amplification feature of a power grid are accurately measured.